Age and its impact on crisis management performance and learning after simulation-based education by acute care physicians: a multicentre prospective cohort study.

BACKGROUND: Physiological changes associated with ageing could negatively impact the crisis resource management skills of acute care physicians. This study was designed to determine whether physician age impacts crisis resource management skills, and crisis resource management skills learning and retention using full-body manikin simulation training in acute care physicians. METHODS: Acute care physicians at two Canadian universities participated in three 8-min simulated crisis (pulseless electrical activity) scenarios. An initial crisis scenario (pre-test) was followed by debriefing with a trained facilitator and a second crisis scenario (immediate post-test). Participants returned for a third crisis scenario 3-6 months later (retention post-test). RESULTS: For the 48 participants included in the final analysis, age negatively correlated with baseline Global Rating Scale (GRS; r=-0.30, P<0.05) and technical checklist scores (r=-0.44, P<0.01). However, only years in practice and prior simulation experience, but not age, were significant in a subsequent stepwise regression analysis. Learning from simulation-based education was shown with a mean difference in scores from pre-test to immediate post-test of 2.28 for GRS score (P<0.001) and 1.69 for technical checklist correct score (P<0.001); learning was retained for 3-6 months. Only prior simulation experience was significantly correlated with a decreased change in learning (r=-0.30, P<0.05). CONCLUSIONS: A reduced amount of prior simulation training and increased years in practice, but not age on its own, were significant predictors of low baseline crisis resource management performance. Simulation-based education leads to crisis resource management learning that is well retained for 3-6 months, regardless of age or years in practice.

Tranexamic acid for the prevention of postpartum haemorrhage: the TAPPH-1 pilot randomized trial and lessons learned for trials in Canadian obstetrics.

Postpartum haemorrhage (PPH) is a leading cause of maternal morbidity and mortality. While tranexamic acid (TXA) reduces bleeding and transfusion requirements in established PPH, we sought to determine the feasibility of conducting a fully powered trial assessing the effect of prophylactic tranexamic acid, prior to PPH onset, in a Canadian Obstetric setting. With institutional and Health Canada approval, consenting, eligible parturients (singleton, > 32 weeks gestation, vaginal or caesarian delivery) were randomly assigned to receive TXA (1 g intravenously) or placebo (0.9% saline) prior to delivery. Participants, investigators, data collectors/adjudicators, and analysis was blinded. The primary outcome was administration of study intervention to > 85% of randomized individuals. Secondary outcomes included recruitment rate (feasibility) and safety outcomes. Over 8 months, 611 were approached, 35 consented, and 27 randomized (14 TXA, 13 placebo). 89% of randomized participants received the assigned intervention. Recruitment fell below feasibility (23% target). No serious adverse outcomes occurred. Our pilot trial in a Canadian Obstetric setting was unable to demonstrate feasibility to conduct a large, multicentre trial to examine prophylactic use of tranexamic for PPH secondary to the complex regulatory requirements associated with a trial for an off-label, but commonly utilized intervention. These challenges should inform stakeholders on the resources and challenges of conducting future trials using off-label interventions.Trial registration: www.clinicaltrials.gov , NCT03069859 (03/03/2017).

Cervical cord myelin abnormality is associated with clinical disability in multiple sclerosis.

BACKGROUND: Myelin water imaging (MWI) was recently optimized to provide quantitative in vivo measurement of spinal cord myelin, which is critically involved in multiple sclerosis (MS) disability. OBJECTIVE: To assess cervical cord myelin measurements in relapsing-remitting multiple sclerosis (RRMS) and progressive multiple sclerosis (ProgMS) participants and evaluate the correlation between myelin measures and clinical disability. METHODS: We used MWI data from 35 RRMS, 30 ProgMS, and 28 healthy control (HC) participants collected at cord level C2/C3 on a 3 T magnetic resonance imaging (MRI) scanner. Myelin heterogeneity index (MHI), a measurement of myelin variability, was calculated for whole cervical cord, global white matter, dorsal column, lateral and ventral funiculi. Correlations were assessed between MHI and Expanded Disability Status Scale (EDSS), 9-Hole Peg Test (9HPT), timed 25-foot walk, and disease duration. RESULTS: In various regions of the cervical cord, ProgMS MHI was higher compared to HC (between 9.5% and 31%, p ⩽ 0.04) and RRMS (between 13% and 26%, p ⩽ 0.02), and ProgMS MHI was associated with EDSS (r = 0.42-0.52) and 9HPT (r = 0.45-0.52). CONCLUSION: Myelin abnormalities within clinically eloquent areas are related to clinical disability. MWI metrics have a potential role for monitoring subclinical disease progression and adjudicating treatment efficacy for new therapies targeting ProgMS.

Myelin Oligodendrocyte Glycoprotein (MOG) Antibody Positive Patients in a Multi-Ethnic Canadian Cohort.

Introduction: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease is a recently described central nervous system (CNS) inflammatory disorder with phenotypic overlap with Neuromyelitis Optica Spectrum Disorder (NMOSD). NMOSD seronegative patients, and those with limited forms of the disorder, become suspects for MOG antibody-associated disease. We describe a multi-ethnic population with MOG antibody seropositivity from the University of British Columbia MS/NMO clinic. Methods: AQP4-antibody seronegative patients presenting 2005-2016 with CNS inflammatory disease suspicious for NMOSD, as well as 20 MS controls, were retrospectively tested for MOG-IgG1 antibodies by live cell-based assay at Oxford Autoimmune Neurology Diagnostic Laboratory (UK) and by a commercial fixed cell-based assay at MitogenDx (Calgary, Canada). Additional MOG seropositive cases were identified through routine clinical interaction (2016-2018) using one of these laboratories. Clinical data was reviewed retrospectively. Results: Retrospective testing identified 21 MOG seropositives (14 by live assay only, 3 by fixed assay only and 4 by both) representing 14% of the "NMOSD suspects" cohort. One multiple sclerosis (MS) control serum was MOG seropositive. Twenty additional MOG positive cases were identified prospectively. Of 42 patients (27 female), median disease onset age was 29 years (range 3-62; 9 pediatric cases), 20 (47%) were non-Caucasian, and 3 (7%) had comorbid autoimmune disease. Most common onset phenotypes were optic neuritis (23, 55%; 8 bilateral) and myelitis (9, 21%; 6 longitudinally extensive) Three of the patients in our cohort experienced cortical encephalitis; two presented with seizures. Onset was moderate-severe in 64%, but 74% had good response to initial steroid therapy. Cumulative relapse probability for the MOG positive group at 1 year was 0.428 and at 4 years was 0.628. Most had abnormal brain imaging, including cortical encephalitis and poorly demarcated subcortical and infratentorial lesions. Few "classic MS" lesions were seen. Optic nerve lesions (frequently bilateral) were long and predominantly anterior, but 5 extended to the chiasm. Spinal cord lesions were long and short, with involvement of multiple spinal regions simultaneously, including the conus medullaris. Conclusions: Our MOG seropositive patients display phenotypes similar to previous descriptions, including cortical lesions with seizures and conus medullaris involvement. Many patients relapsed, predominantly in a different CNS location from onset. Serologic data from two different cell-based antibody assays highlight the discrepancies between live and fixed testing for MOG antibodies.

Comparison of the effects of perineural or intravenous dexamethasone on low volume interscalene brachial plexus block: a randomised equivalence trial.

BACKGROUND: Efforts to prolong interscalene block (ISB) analgesia include the use of local anaesthetic adjuvants such as dexamethasone. Previous work showing prolonged block duration suggests that both perineural and intravenous (i.v.) routes can both prolong analgesia. The superiority of either route is controversial given the design of previous studies. As perineural dexamethasone is an off-label use, anaesthesiologists should be fully informed of the clinical differences, if any, on block duration. This study was designed to test whether perineural vs i.v. dexamethasone administration are equivalent. METHODS: We randomised 182 eligible patients scheduled for arthroscopic shoulder surgery to receive low-dose ISB (0.5% ropivacaine 5 ml) with perineural or i.v. dexamethasone 4 mg. Subjects, anaesthesiologists, and research personnel were blinded. All subjects also received a standardised general anaesthetic and multimodal analgesia. The primary outcome was duration of analgesia analysed as an equivalence outcome (2 h equivalency margin) using the two one-sided test (TOST) method. RESULTS: For the primary outcome, duration of analgesia, and perineural and i.v. administration of dexamethasone were not equivalent. The upper and lower bounds of the 90% confidence interval were 1 h (P=0.12) and -2.5 h (P=0.01), respectively. The observed difference in mean block duration was not clinically relevant (0.75 h longer for i.v. dexamethasone). There were no other clinically significant differences between groups. CONCLUSION: In the context of low-volume ISB with ropivacaine, perineural and i.v. dexamethasone were not equivalent in terms of their effects on block duration. However, there were no clinically significant differences in outcomes, and there is no advantage of perineural over intravenous dexamethasone. WWW.CLINICALTRIALS. GOV REGISTRATION: NCT02322242.

Protocol for a prospective cohort study of assessing postoperative cognitive changes after total hip and knee arthroplasty in the Greater Toronto area.

INTRODUCTION: Cognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium exist, there are no effective treatment strategies for POCD. Understanding the risks and contributing factors may offer clinicians unique opportunities to better identify and develop preventative interventions for those at higher risk. Elderly patients undergoing orthopaedic surgery are at high risk of developing postoperative delirium (PD) and POCD. The incidence of POCD has not been rigorously studied in the total hip and knee arthroplasty (THA/TKA) population. Therefore, we have designed a prospective, observational cohort study to assess POCD in patients undergoing THA/TKA, both increasingly common procedures. The incidence of PD and POCD in a high volume, tertiary care arthroplasty centre will be determined and associated risk factors will be identified. METHODS AND ANALYSIS: Cognitive function will be tested with a computer-based cognitive assessment tool [CogState Brief Battery], preoperatively at baseline and postoperatively while in hospital at (<3 days), 6 weeks and 4.5 months. The primary outcome is the incidence of postoperative cognitive decline at 4.5 months. Logistic regression analysis is planned to test the association of POCD with several potential risk factors. In addition, delirium will be assessed preoperatively and postoperatively in the hospital using the Confusion Assessment Method (3D-CAM). ETHICS AND DISSEMINATION: The protocol for this prospective observational study was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (REB#: 040-2017). Recruitment commenced in May 2017 and will continue until 2019. The results will be disseminated in a peer-reviewed journal and in scientific meetings. TRIAL REGISTRATION NUMBER: NCT03147937.

Does the age of acute care physicians impact their (1) crisis management performance and (2) learning after simulation-based education? A protocol for a multicentre prospective cohort study in Toronto and Ottawa, Canada.

INTRODUCTION: The proportion of older acute care physicians (ACPs) has been steadily increasing. Ageing is associated with physiological changes and prospective research investigating how such age-related physiological changes affect clinical performance, including crisis resource management (CRM) skills, is lacking. There is a gap in the literature on whether physician's age influences baseline CRM performance and also learning from simulation. We aim to investigate whether ageing is associated with baseline CRM skills of ACPs (emergency, critical care and anaesthesia) using simulated crisis scenarios and to assess whether ageing influences learning from simulation-based education. METHODS AND ANALYSIS: This is a prospective cohort multicentre study recruiting ACPs from the Universities of Toronto and Ottawa, Canada. Each participant will manage an advanced cardiovascular life support crisis-simulated scenario (pretest) and then be debriefed on their CRM skills. They will then manage another simulated crisis scenario (immediate post-test). Three months after, participants will return to manage a third simulated crisis scenario (retention post-test). The relationship between biological age and chronological age will be assessed by measuring the participants CRM skills and their ability to learn from high-fidelity simulation. ETHICS AND DISSEMINATION: This protocol was approved by Sunnybrook Health Sciences Centre Research Ethics Board (REB Number 140-2015) and the Ottawa Health Science Network Research Ethics Board (#20150173-01H). The results will be disseminated in a peer-reviewed journal and at scientific meetings. TRIAL REGISTRATION NUMBER: NCT02683447; Pre-results.

The chaperone dynein LL1 mediates cytoplasmic transport of empty and mature hepatitis B virus capsids.

BACKGROUND & AIMS: Hepatitis B virus (HBV) has a DNA genome but replicates within the nucleus by reverse transcription of an RNA pregenome, which is converted to DNA in cytoplasmic capsids. Capsids in this compartment are correlated with inflammation and epitopes of the capsid protein core (Cp) are a major target for T cell-mediated immune responses. We investigated the mechanism of cytoplasmic capsid transport, which is important for infection but also for cytosolic capsid removal. METHODS: We used virion-derived capsids containing mature rcDNA (matC) and empty capsids (empC). RNA-containing capsids (rnaC) were used as a control. The investigations comprised pull-down assays for identification of cellular interaction partners, immune fluorescence microscopy for their colocalization and electron microscopy after microinjection to determine their biological significance. RESULTS: matC and empC underwent active transport through the cytoplasm towards the nucleus, while rnaC was poorly transported. We identified the dynein light chain LL1 as a functional interaction partner linking capsids to the dynein motor complex and showed that there is no compensatory transport pathway. Using capsid and dynein LL1 mutants we characterized the required domains on the capsid and LL1. CONCLUSIONS: This is the first investigation on the detailed molecular mechanism of how matC pass the cytoplasm upon infection and how empC can be actively removed from the cytoplasm into the nucleus. Considering that hepatocytes with cytoplasmic capsids are better recognized by the T cells, we hypothesize that targeting capsid DynLL1-interaction will not only block HBV infection but also stimulate elimination of infected cells. LAY SUMMARY: In this study, we identified the molecular details of HBV translocation through the cytoplasm. Our evidence offers a new drug target which could not only inhibit infection but also stimulate immune clearance of HBV infected cells.

Protocol for a pilot, randomised, double-blinded, placebo-controlled trial of prophylactic use of tranexamic acid for preventing postpartum haemorrhage (TAPPH-1).

INTRODUCTION: Postpartum haemorrhage (PPH) is the leading cause of maternal morbidity and mortality worldwide. Despite the availability of multiple uterotonic agents, the incidence of PPH continues to rise. Tranexamic acid (TXA) has been shown to be a safe, effective and inexpensive therapeutic option for the treatment of PPH, however, its use prophylactically in mitigating the risk of PPH is unknown. This pragmatic randomised prospective trial assesses the feasibility and safety of administering TXA at the time of delivery for the prevention of PPH. METHODS AND ANALYSIS: A pilot pragmatic randomised double-blinded placebo-controlled trial will be performed. 58 singleton parturients at term >32 weeks, undergoing either spontaneous vaginal delivery, or caesarean section will be randomised to receive 1 g of TXA or placebo (0.9% saline) intravenously. The primary outcome assessed will be the feasibility of administrating TXA, along with collecting data regarding safety of drug administration. The groups will also be analysed on efficacy of mitigating the onset of PPH and clinically relevant variables. Demographic, feasibility, safety and clinical endpoints will be summarised and the appropriate measures of central tendency and dispersion will be presented. ETHICS AND DISSEMINATION: This protocol was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (number: 418-2016). The results will be disseminated in a peer-reviewed journal and at scientific meetings. TRIAL REGISTRATION NUMBER: NCT03069859; Pre-results.

A new mechanism for nuclear import by actin-based propulsion used by a baculovirus nucleocapsid.

The transport of macromolecules into the nucleus is mediated by soluble cellular receptors of the importin ß superfamily and requires the Ran-GTPase cycle. Several studies have provided evidence that there are exceptions to this canonical nuclear import pathway. Here, we report a new unconventional nuclear import mechanism exploited by the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV). We found that AcMNPV nucleocapsids entered the nucleus of digitonin-permeabilized cells in the absence of exogenous cytosol or under conditions that blocked the Ran-GTPase cycle. AcMNPV contains a protein that activates the Arp2/3 complex and induces actin polymerization at one end of the rod-shaped nucleocapsid. We show that inhibitors of Arp2/3 blocked nuclear import of nucleocapsids in semi-permeabilized cells. Nuclear import of nucleocapsids was also reconstituted in purified nuclei supplemented with G-actin and Arp2/3 under actin polymerization conditions. Thus, we propose that actin polymerization drives not only migration of baculovirus through the cytoplasm but also pushes the nucleocapsid through the nuclear pore complex to enter the cell nucleus. Our findings point to a very distinct role of actin-based motility during the baculovirus infection cycle.

Baculovirus nuclear import: open, nuclear pore complex (NPC) sesame.

Baculoviruses are one of the largest viruses that replicate in the nucleus of their host cells. During infection, the rod-shape, 250-nm long nucleocapsid delivers its genome into the nucleus. Electron microscopy evidence suggests that baculoviruses, specifically the Alphabaculoviruses (nucleopolyhedroviruses) and the Betabaculoviruses (granuloviruses), have evolved two very distinct modes for doing this. Here we review historical and current experimental results of baculovirus nuclear import studies, with an emphasis on electron microscopy studies employing the prototypical baculovirus Autographa californica multiple nucleopolyhedrovirus infecting cultured cells. We also discuss the implications of recent studies towards theories of nuclear transport mechanisms.

Nuclear transport of baculovirus: revealing the nuclear pore complex passage.

Baculoviruses are one of the largest viruses that replicate in the nucleus of their host cells. During an infection the capsid, containing the DNA viral genome, is released into the cytoplasm and delivers the genome into the nucleus by a mechanism that is largely unknown. Here, we used capsids of the baculovirus Autographa californica multiple nucleopolyhedrovirus in combination with electron microscopy and discovered this capsid crosses the NPC and enters into the nucleus intact, where it releases its genome. To better illustrate the existence of this capsid through the NPC in its native conformation, we reconstructed the nuclear import event using electron tomography. In addition, using different experimental conditions, we were able to visualize the intact capsid interacting with NPC cytoplasmic filaments, as an initial docking site, and midway through the NPC. Our data suggests the NPC central channel undergoes large-scale rearrangements to allow translocation of the intact 250-nm long baculovirus capsid. We discuss our results in the light of the hypothetical models of NPC function.

How viruses access the nucleus.

Many viruses depend on nuclear proteins for replication. Therefore, their viral genome must enter the nucleus of the host cell. In this review we briefly summarize the principles of nucleocytoplasmic transport, and then describe the diverse strategies used by viruses to deliver their genomes into the host nucleus. Some of the emerging mechanisms include: (1) nuclear entry during mitosis, when the nuclear envelope is disassembled, (2) viral genome release in the cytoplasm followed by entry of the genome through the nuclear pore complex (NPC), (3) capsid docking at the cytoplasmic side of the NPC, followed by genome release, (4) nuclear entry of intact capsids through the NPC, followed by genome release, and (5) nuclear entry via virus-induced disruption of the nuclear envelope. Which mechanism a particular virus uses depends on the size and structure of the virus, as well as the cellular cues used by the virus to trigger capsid disassembly and genome release. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.

Microinjection of Xenopus laevis oocytes as a system for studying nuclear transport of viruses.

Microinjection of Xenopus laevis oocytes is an excellent system for studying nuclear transport because of the large size of the oocyte and its high nuclear pore complex (NPC) density. In addition, the fact that Xenopus oocytes are not permissive for most mammalian viruses makes this system especially useful for studying nuclear transport of viruses in the absence of the confounding factor of virus replication. In this article, we briefly discuss the contribution of microinjection of Xenopus oocytes to the field of nuclear transport. We then describe the protocols we have developed using microinjection of Xenopus oocytes to study nuclear transport of viral capsids, and summarize variations of the technique that can be used to address many different questions about the nuclear transport of viruses.

Microinjection of Xenopus laevis oocytes.

Microinjection of Xenopus laevis oocytes followed by thin-sectioning electron microscopy (EM) is an excellent system for studying nucleocytoplasmic transport. Because of its large nucleus and high density of nuclear pore complexes (NPCs), nuclear transport can be easily visualized in the Xenopus oocyte. Much insight into the mechanisms of nuclear import and export has been gained through use of this system (reviewed by Panté, 2006). In addition, we have used microinjection of Xenopus oocytes to dissect the nuclear import pathways of several viruses that replicate in the host nucleus. Here we demonstrate the cytoplasmic microinjection of Xenopus oocytes with a nuclear import substrate. We also show preparation of the injected oocytes for visualization by thin-sectioning EM, including dissection, dehydration, and embedding of the oocytes into an epoxy embedding resin. Finally, we provide representative results for oocytes that have been microinjected with the capsid of the baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV) or the parvovirus Minute Virus of Mice (MVM), and discuss potential applications of the technique.